Chronograph results

[Justintoxicated]

Shot a bunch of loads and decided on this hot load of 43.5gr varget for 175gr SMK for my R700. I say hot because the primers are flattening a bit and I see some light cratering on the primers.

In order to get better results from my ballistic calculator, I chronographed the load. This is only my second time using the thing and at first it was giving me some errors (error 9). This was using a shooting chrony it did seem top pickup every shot. It was placed about 10-12 feet from the rifle.

2568
2593
2587
2601
2621
2601
2605
2589
2590
2598
2607

Should I throw out the highest and lowest results, then average the rest, or just average all of the numbers or what? My friend says my loads are not good because the deviation between the highest and lowest numbers is high about 50fps.

I did hand weigh each of the rounds, brass was LC from 2000, all cases were trimmed fire-formed, then neck sized using a bushing die, then trimmed to uniform length (maybe a couple pieces were a little off) before loading them this last time.

Appreciate any feedback, thanks!

I seemed to only be getting about 6" groups at 300 yards off a bipod, but I think this failure is mostly me not timing my heartbeat correctly, or just having a hard time pulling the trigger at that exact moment, or maybe even the wind since I was mostly getting horizontal stringing. I do not have the most steady hands in the world, and I ALWAYS pull the 5th shot in my near perfect groups at 100 yards still (meaning nice clover pattern never makes it to the 5th shot :P

[rsrocket1]

I would think the groups would tell you whether the load is good or not. The whole idea of finding a node is that the shots will still be landing at the same spot regardless of small deviations in the other parameters (differences in MV in this case). 6" @ 300 yards is 1.9 MOA which is not a bad start. Did you do this in a dead calm day? A 3 MPH wind at 90 degrees will throw the shots off by 2" at 300 yards and a 5 MPH wind will throw them off 4-1/2" at that range. What was your vertical stringing distance? That will tell you whether or not the MV is making a difference.

I don't throw out any shots from a string. I simply keep records of what really happened. My records are for telling like it is and not a "brag board". If you are hunting or in a competition, you usually don't get throw-outs so I want to see what happens to the shot string as I shoot them. If I see a trend of MV's or a first shot flyer that's important to know.

Assuming your COL is 2.80", QL says your load is at 56,000 psi which is below SAAMI max but pretty close and that a 24" barrel should get you about 2630 fps so your average MV of 2596 is pretty much spot on for that load. A 2% extreme spread is pretty good and you SD is 14 fps which is very good. I would say your load technique is good. You should now try different loads (probably lower for safety sake, I wouldn't go up much more) and see if the groups shrink. You might want to try 100 yards until you get a really small group in order to eliminate the wind variable.

[acourvil]

The shooting chrony and others in it's class aren't that accurate unless the lighting is just right, and passing clounds and other variations in light can cause variations in the reported speeds. It's better than nothing, and will give you a good esitmate, but it's no going to measure well enough that you can rely on the SD as a strong indication of your load. If your groups are good, don't worry about it.

As far as your 300 yard groups, if you re mainly getting horizontl stringing that's more likely wind and technique.

[spamsucker]

1. How bad are the primers? Post pics.
2. How are you dispensing charges? Are you throwing them or weighing each one?

I ask because your load isn't actually that bad on paper. The SD is relatively low and even if the ES is a little tall those aren't all that bad. I shoot for <10fps SD's myself in target ammo. I've had a lot of factory ammo that was no more consistent than yours though.

13.55 stdev
53 es
2598 median
2596 average

That it's not printing well is not a surprise. Hot loads very rarely do in my experience, they end up a little volatile. Pull back the throttle a little, your brass will last longer and I bet your ammo will get more consistent. Some things like to be hot rodded but not many.

[Justintoxicated]

My other accuracy node is 42.6gr varget, still has a bit flattened primers and slight cratering. Both these loads are capable of shooting one hole groups that are about 1/2 moa at 100 yards. 42.6 gave me a nice clover pattern (minus the shot I pulled) where as the 43.5 load even tightened that up a bit more. Test loads were shot @100 yards indoors so no wind, so I selected 43.5gr to bnring to the outdoor range for more testing. the larger groups at 300 yards were probably just me screwing up as I had not shot the thing in about 6 months.

Wind was probably on and off around 2-3mph at most so a pretty calm day. Range didn't have any flags down rage at the time so it's hard to say how much breeze there was at 300 yards.

COAL was longer than 2.80 as I was seating the bullets .025" from the lands (measured on my rifle). Had to load them one at a time into the rifle as they would not fit in the magazine.

Not the best chrony but better than nothing, I bought it because I wasn't sure how much I really needed it at the time and was afraid of blasting an expensive one with one of my milsurps. So should I remove the high and low then calculate the average to use in my ballistics table at the next competition or should I leave them in for averaging the velocity?

Rounds were dispensed then checked on a hornady GS 350 scale. I did load the rounds on a progressive because I was too lazy to swap back to my single stage since I only had 24 hours notice and wanted to shoot something, but I doubt the difference is from that.

Yes I need more practice, I have only shot this rifle 3 times. Pretty new to all this long range stuff, I don't think I will ever be great as I'm not the most steady shot but it's still fun. It becomes real apparent if I zoom the scope to 30x.

Guess I need to just get out there and try again. Maybe I should load some more 42.6gr loads as well.

[J-cat]

Cratering and slight flattening is not a pressure sign in a Remmy.

[NorCalFocus]

Cratering and slight flattening is not a pressure sign in a Remmy.

THIS^^^

All my loads from min to max have cratering on the primers. I don't have flat, flat edges and my bolt doesn't stick. If your the same continue on.

Your giving to much thought to the chrono. Load and do your ladder test at 100, 300 and see which load groups best. Then go back with the best load and try different seating depths. See if the groups tighten up even more.

Once you have a load that shoots good, chrono that load, strictly to get an average speed to build your drop chart

[JTROKS]

What brand primers did you use? If Federal Large Rifle then that's about the softest. Work up a load using Remington or CCI Large Rifle primers may alleviate the primer cratering. Did you switch your firing pin to light titanium?

[Justintoxicated]

THIS^^^

All my loads from min to max have cratering on the primers. I don't have flat, flat edges and my bolt doesn't stick. If your the same continue on.

Your giving to much thought to the chrono. Load and do your ladder test at 100, 300 and see which load groups best. Then go back with the best load and try different seating depths. See if the groups tighten up even more.

Once you have a load that shoots good, chrono that load, strictly to get an average speed to build your drop chart

Already found the best load and accuracy nodes at 100 yards indoors, I wanted to chrono the results for my ballistic calculator I will use at the next match. Varying distance to targets (but known distances) out to 800 yards or so. Last time my data matched up somewhat (made nearly every shot out to about 400 yards then I couldn't hit anything past about 500 yards so the ballistic table must have been off and it's impossible to guess your next shot without some way to see where your bullet hits.

What brand primers did you use? If Federal Large Rifle then that's about the softest. Work up a load using Remington or CCI Large Rifle primers may alleviate the primer cratering. Did you switch your firing pin to light titanium?

They are Tula primers, not ideal but I purched 10k last year during the shortage (the only way to get them under $30 for 1000).

I do not have a titanium firing pin, just a mostly stock (other than trigger) R700 Mil-spec 5R

[bsumoba]

ejector marks, ejector swipes, cratering, flattening, dark burn edges around the edge of the primers, etc are all indicators that tell a story and its up to you to determine if it is a true high pressure condition situation.

I know of one guy that told me to do a load work up until I pretty much got a popped or pierced primer, or a huge ejector mark on the case head.

I know another guy that says he stops when he sees heavy cratering along with flattening.

Primers are also different. I noticed Winchester will flatten almost all the time. CCI is less prone to flattening due to their slightly harder cup, and federal is somewhere in between.

Just all depends.

do vertical testing at 300+, which indicates whether or not you are in a node region of the powder charge. then your accuracy tests at 100-200 yards. Then, take the most accurate load and go back out to distance to verify. i know thats all in a nutshell, but if you want to know how i do my load development, PM me.